"United States Census, 1930," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:X4Z2-2S6 : accessed 26 June 2018), James F Arnott in household of J A Arnott, Belpre, Washington, Ohio, United States; citing enumeration district (ED) ED 7, sheet 8B, line 95, family 210, NARA microfilm publication T626 (Washington D.C.: National Archives and Records Administration, 2002), roll 1887; FHL microfilm 2,341,621.
"United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:KWGX-VG5 : accessed 26 June 2018), James Arnott in household of James A Arnott, Belpre Township, Washington, Ohio, United States; citing enumeration district (ED) 84-8, sheet 14A, line 6, family 283, Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 - 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012, roll 3165.
It may be possible to confirm family relationships with James by comparing test results with other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with James: